DCI w/ Variants

digital_delivery.rb

class DigitalDelivery
  attr_reader :order

  def self.call(order)
    digtial_order = order.extend(DigitalOrder)
    deliverer = new(digital_order)
    # do stuff to get it delivered
    deliverer
  end

  def initialize(order)
    @order = order
  end 
end

digital_order.rb

module DigitalOrder
  include OrderRecord

  # behavior for a digital order?
end

order.rb

class Order
  def self.variant_from(opts={})
    [opts[:type], new(opts)]
  end
end

order_record.rb

module OrderRecord
  include CoolORM

  # define schema via a cool dsl and stuff...
end

orders_controller.rb

require 'nifty-variants'

class OrdersController < ApplicationController
  responds_to :json, :html

  def create
    context = cases Order.variant_from(order_params),
                digital: ->(o) { DigitalDelivery.call(o) },
                in_store: ->(o) { InStoreDelivery.call(o) },
                home_delivery: ->(o) { HomeDelivery.call(o) }
    respond_with(context.order)
  end

  private
  def order_params
    params.permit(:type, :address, :email, :store_id, :item_id)
  end
end